Present invention relates in general to belt clutches and in particular to apparatus for reducing drag when a belt clutch is disengaged.
Belt clutches engage traction pulleys to transmit torque from one shaft to at least one other shaft and disengages to stop the torque from being transmitted. Some known belt clutches that are engaged by either moving an idler pulley against a belt to tighten it around the traction pulleys and disengaged by moving it away to loosen the belt. Other belt clutches are engaged by moving one of the traction pulleys away from the other traction pulley and disengaged by moving the traction pulleys together. Both types of belt clutches share a common problem. When the clutch is disengaged, the belt is normally still in contact with belt surfaces of the traction pulleys which are moving at different speeds. This creates a significant amount of undesirable drag and belt wear.
If an enclosure is correctly positioned around the perimeter of the belt of an engaged belt clutch, when the belt clutch is disengaged, the inside surface of the enclosure will constrain the belt in a position which causing the belt to separate from the traction pulleys. This allows the traction pulleys to rotate freely without dragging on the belt and provides a very simple and efficient combination clutch and speed reducing or speed increasing, power transmission device.
However, the mere presence of an enclosure around the belt still has disadvantages. When the belt is disengaged at high speed and moves out against the enclosure, the belt hits some parts of the stationary enclosure, causing the belt to rapidly bounce around between the pulleys and the enclosure, causing vibration, noise, added wear, heat, and loss of efficiency. Accordingly, a need remains for a simple belt clutch mechanism which biases the belt away from the traction pulleys and eliminates the belt drag and vibration when disengaged or being disengaged during operation up to its rated speed.